import java.util.Scanner;


public class Test {
    //罗马数字转整数    链接:https://leetcode.cn/problems/roman-to-integer/description/
    public int romanToInt(String s) {
        int ret = 0;
        char[] arr = s.toCharArray();
        for(int i = arr.length - 1;i >= 0;i--){
            char c = arr[i];
            switch(c){
                case 'I':
                    ret += (ret>=5 ? -1:1);
                    break;
                case 'V':
                    ret += 5;
                    break;
                case 'X':
                    ret +=(ret >= 50? -10:10);
                    break;
                case 'L':
                    ret += 50;
                    break;
                case 'C':
                    ret +=(ret >= 500? -100 : 100);
                    break;
                case 'D':
                    ret += 500;
                    break;
                case 'M':
                    ret += 1000;
                    break;
            }
        }
        return ret;
    }


    public static void main(String[] args) {
        //先输入  多组输入
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNext()) {
            String str1 = scanner.next();
            String str2 = scanner.next();
            int len1 = scanner.nextInt();
            int len2  = scanner.nextInt();


            //  要吧字符串分别补成最长的  那个len  都要补相同   如果对应最长的len2是3   每个字符串都要补成3的长度
            for (int i = str1.length(); i < len2; i++) {
                //补a  因为是一开始的位置
                str1 = str1 + 'a';
            }

            //同样 str2也要补  不过是补到z+1  //因为要  去掉边界那个
            for (int i = str2.length(); i < len2; i++) {
                str2 = str2 + 'z' + 1;
            }


        }
    }
}
